Fire-extinguishing pump



June 11, 1946. zlEScHANG 2,401,785

FIRE-EXTINGUISHING PUMP Filed June 21, 1944 5 Sheets-Sheet l A ltorneys .Time 11, 1946. R. ZIESCHANG 2,401,785

' FIRE-EXTINGUISHING PUMP Filed June 21, 1944 5 Sheets-Sheet 2 Inventor ZQ/MZ ztzgow 9964 W A ltorneys June 1946- R. ZIESCHANG FIRE-EXTINGUISHING PUiVIP Filed June 21, 1944 5 Sheets-Sheet 3 A ltomeys June 11, 1946. R. zlEscHANG FIRE-EXTINGUISHING PUMP F iled June 21, 1944 5 Sheets-Sheet 4 IMT w i .1, L Y 6 Patented June 11, 1946 2,401,785 FIRE-EXTINGUISHING PUMP Richard Zieschang, Brentford, England, assignor to The Pyrene Company Limited, Brentford,

England, a British company Application June 21, 1944, Serial No. 541,415 In Great Britain July 1, 1943 11 Claims.

This invention relates to hand-operated doubleacting pumps of the kind in which a piston reciprocates in a cylinder placed within a container for liquid to be expelled. The invention is particularly applicable, although not limited, to pumps of this kind in which the piston is carried by a hollow piston rod formed with inlet ports controlled by the piston and which are intended for use either way up and are in common use as fire-extinguishers.

In such pumps the liquid must be drawn in from the bottom of the container and a nonreturn valve must be placed here, because other wise that valve will not remain immersed in liquid as the liquid level falls during the operation of the pump. It is necessary to ensure that on the down-stroke (whichever way up the pump is held) liquid enters the part of the cylinder above the piston so that this part will contain liquid which can be forced out of it into the hollow piston rod on the up-stroke. In the existing pumps there are two non-return valves, one at each end of the cylinder, and these are not directly exposed to the interior of the container but instead lie in the wall of a suction tube that runs throughout substantially the whole length of the container, so that on the down-stroke the liquid is drawn into the cylinder through this suction tube and the upper non-return valve.

As the existing pumps of this kind that are used as fire extinguishers are intended for use either end up, the suction tube is itself provided at each end with an inlet controlled by a ball valve, the upper ball being on its seat and the lower ball off its seat in use. To ensure positive movement of the lower ball off its seat a rod is placed in the suction tube to slide into contact with the lower ball. Being loosely mounted, the rod and the ball valves are liable to rattle if the extinguisher is subjected to vibration or moved, particularly if it is carried in a horizontal position on a motor car, and this rattling is undesirable.

Apart from the desirability of eliminating this relatively minor disadvantage and simplifying the construction of the pump, there is an important factor that must be taken into account. When the pump is used as a fire extinguisher it should ideally deliver an equal volume on each stroke and should continue to deliver that volume at each stroke from the beginning to the end of the pumping. Now it is easier for the average person to direct the jet accurately and control and operate the pump easily and uniformly if the pump is made to eject slightly less liquid on the outward stroke than the inward stroke, so that the work required corresponds to the directive eiiort normally available. Since the pumps are generally pointed downwards onto fires, it is the outward up-stroke that requires less effort than the inward down-stroke, and consideration of what happens when the pump is pointed upwards is of less importance. In the existing pumps of the kind in question the difference in the amounts of muscular energy required is an inevitable result of the construction, which is such that at every stroke only about one quarter of the liquid in the cylinder on the leading or high-pressure side of the piston is discharged as a jet and the remainder is forced back into the container through bearings in which the whole cylinder assembly is rotatably mounted in the pump. On the downward in-stroke the bearings in question are immersed in liquid and the resistance to the passage of liquid through them is greater than that on the upward out-stroke, when the bearings through which the liquid is forced are not immersed. This difference in resistance both makes it possible to operate the pump uniformly without requiring an unnatural effort on the outward stroke and results in the discharge of a smaller Volume on that stroke than on the inward stroke. However it is accompanied by an important disadvantage, namely that when the amount of liquid in the container is getting low the jet of liquid is reduced in volume and just towards the end of the complete operation it becomes completely irregular, My object is to provide a pump which will deliver the predetermined volumes of liquid at each stroke from the beginning to the end of the pumping and which will be free from the other disadvantages referred to.

In the existing pumps there is a distinct halt or check in the discharge of liquid on the changeover from the downward in-stroke to the upward out-stroke, and irrespectively of any difference in the volumes ejected on the two strokes this leads to irregularity in the discharge of liquid. We aim also at reducing or eliminating this halt or check.

A further result of the existing form of construction is that it is necessary to provide a device for stripping liquid from the hollow piston rod immediately beyond the bearing at the end of the pump at which the piston rod passes out through the head of the container to be joined to an operating handle. We aim further at eliminating the need for such a stripping device.

According to this invention I use a composite piston assembly comprising a piston formed with one or more axial passages and a clack valve on the side of the piston nearer to the operating handle, the whole assembly reciprocating at each stroke through a continuous column of liquid and driving before it a specific fraction of the liquid in the cylinder on the forward side of the assembly, the remainder passing through the assembly to its rearward side. The principle involved may be more easily understood by considering a pump cylinder full of liquid and con- 3 taining a piston working in fluid-tight fashion within it. If the cylinder were closed at both ends and the piston rod tightly packed the piston '(if solid) would be immovable; if on the other hand large axial openings were made in the piston it would pass through the liquid with such ease that there would be only a negligible discharge of liquid. If, however, restricted axial openings are made in the piston, the latter can still be reciprocated with ease but enough resistance will be ofifered to its passage to give the pressure required to force a fraction of the liquid out of the cylinder to the discharge nozzle. In the absence of any controlling valve it is found in practice, by the construction of many dilferent forms'of'piston for experimental purposes, that with a pump of the same dimensions as those that long experience'has shown to be best in a hand-operated fire extinguisher for 'use either Way. up the optimum result is obtained when the volume of liquid ejected on the downward instroke'is less than that in the existing pumps, and the volume ejected on the outward up-stroke is ,onlyxabout half that of the downward in-stroke. Any attempt to increase the volumes by reducing the size of the axial openings in the piston leads togturbulence and to most erratic results; in addition; undue effort by the operator is required. By'the use of a clack valve it is found possible to solve all the problems that arise.

Preferably I use two clack valves, one on each side of the piston and advantageously these are mechanically interconnected to move as a unit,

The invention will be more clearly understood byreference to the accompanying drawings, in which Figure 1 shows the preferred pump and is principally an axial section;

Figure '2 is an exploded view of the parts forming'the piston assembly;

Figure 3 is an axial section on a larger scale of the piston assembly and associated parts during the down-stroke when the pump is held in the position shown in Figure 1;

Figure 4 is a section similar to Figure 3 but taken during the up-stroke;

Figures 5, 6 and 7 are sections on the lines VV, VI-VI and VIIVII respectively in Figure;3; l

Figures 8 and 9 are sections on the lines VIII- VIII and IXIX respectively in Figure 1; and

Figures wand 11 are sections similar to Figures 3 and 4 through a modified pump assembly. "The pump shown in Figure 1 comprises a container I in which a pump cylinder 2 is mounted to rotate about its own axis, being journalled at the lower'end on a fixed central discharge tube 3 which terminates in a nozzle 4. This tube 3 passes through the closed end of a hollow piston 7 rod 6, which passes through and is journalled in the head i of the pump and in turn forms a bearing for the closed upper end 8 of the cylinder 2. The pistonrod 6 carries an operating handle 9, which is held in the head 7 by a bayonet joint when the pump is not in use and in that position seals the upper end In of the discharge tube 3.

Th cylinder 2 has two inlet ports II and I2 controlled by non-return ball valves i3 and M that are carried in fittings l5 and I6 secured to the cylinder and that engage valve seats I? and 88 respectively in the two fittings. The parts of the pump so far described are identical in principle with equivalent parts in the existing pumps of the kind in question.

The hollow piston rod 6 carries a composite the outward stroke 'formed with three axial passages piston assembly comprising a piston 20 and two valve members such as clack valves 2| and 22. The two latter are rigidly interconnected by rods 23 screw-threaded at their ends to engage in axial bores 2d in the clack valves, the rods mak ing a close sliding fit in axial passages 25 in the piston 25 and being secured by nuts 26. The two clack valves can thus move as a unit relatively to the piston 26. The piston iscircumferenti-ally grooved to receive an expansible sealing ring 21 so that it fits the pump cylinder tightly, and it is 28, 29 and 30. At each end the piston is recessed around its inner edge, as shown at 3| and 32, and it controls ports 33 and 34 in the wall of the piston rod 6. The upper face of'the piston is formed with an annular groove 35, into which the passages 23, 29 and 36 open. The movement of the piston 20 over the piston rod is limited in the upward direction by the end ofa sleeve 35-3 which is sweated onto the piston rod 6 and in the downward direction by the upper end of the cap 5.

The upper clack valve 22 is made with a small but definite clearance 37 around the sleeve 36 and with two axial passages 38 which are out of register with the passages 28, 29 and 30, but in axial register with the groove 35. The lower clack valve 26 is also made With a small but definite clearance 39 around the cap 5 and with two axial passages .19 and 4!, which are also out of register with the passages 23, '29 and 3!). The lower clack valve has an annular projection 43 facing the underface of the piston.

In order to make the amount of liquid expelled on the inward stroke greater than that on the outward stroke, and so to take account of the different muscular efforts naturall available as explained above; a valve may be provided to reduce the flow through the assembly during the inward stroke in comparison with that during the outward stroke. This valve takes the form of a projection Mon the upper surface of the clack valve 2!, so disposed as to close the passage 39 on coming into contact with the lower surface of the piston 2e. 7

In operation, the position of the parts on the inward stroke is shown in Figure 3. The sleeve 36 secured'to the hollow piston rod 6 drives the piston 28 before it, the lower side of the piston is in contact with. the projection 42, and (assuming that the pump is pointing downwards) the valve I 3 is 'on its seat il and the valve i4 is off its seat iii. The valve member 2i, which is then leading, moves through the liquid in the cylinder whichfiows upward through the clearance space 39 and the passages 4t and ll. Some of the'liquid'is forced through the ports 34 into the interior of the piston rod 6, flows up it and then flows down through the discharge tube 3. The remainder'of the liquid displaced passes through the passages 28 and 29 in the piston'tc and into the space between the piston 29 and the valve member 22 and then on through the clearance space 3? and the passages 33 in the valve member 22 to the far side of the piston assembly. On this'inward stroke no liquid is drawn into the pump cylinder if the valve'id is above the liquid line, but the piston assembly moves through a continuous column of liquid and enough liquid passes to theupper side of the piston assembly to ensure efficient operation on the next stroke.

During the change-over from the inward to the liquid in the space between the valve member 22 and the piston 20 may be regardedas trapped, and as the piston moves upwards relatively to the valve this liquid has a cushioning effect and very distinctly reduces the halt or check in the discharge of liquid that occurs in existing pumps of the kind in question. This cushioning effect is found to be increased by the presence of the annular projection 43.

On the outward stroke, the position of the parts is shown in Figure 4. The piston 20 is now being driven by the cap secured to the hollow piston rod 6 and has moved upwards relatively to the clack valves 21 and 22. The liquid above the piston assembly which is displaced fiows through the clearance space 31 and the passages 38 in the valve member 22 and into the groove 35. Some of this displaced liquid flows through the ports 33 into the interior of the hollow piston rod 6, flows up it and down through the discharge tube 3; and the remainder passes through the axial passages 28, 29 and 30 in the piston 20 into the space between it and the valve member 2| and then on through the clearance space 39 and the passages 40 and 4| in the valve member 2| into the bottom of the pump cylinder 2, as the complete piston assembly moves. During this stroke the bottom of the pump cylinder 2 also receives liquid under the action of suction at the valve 13 assisted by the gravity head.

During this outward stroke the liquid flows around the groove 35 on its way from the passages 38 to the passages 28, 29 and 30, that is to say, it flows along a resistance path. It is found in practice that much improved results are obtained by forming the resistance path in this way than by making the axial passages smaller in diameter. An equivalent resistance path is provided on the inward stroke by the fact that the passages 40 and 4! are out of axial register with the passages 28 and 29.

In the modification shown in Figures and .1 there is only one clack valve, this being shown at 44 and mounted above the piston 20. It is carried by pins 45 secured in the valve member 44 which pass freely through bores in the piston 20 and its outward movement relatively to the piston rod 6 is limitedby a shouldered collar 46 which is fixed to the hollow piston rod 6 and which serves on the inward stroke (shown in Figure 10) to close the clearance 31 between the valve member 44 and the piston rod 6. On this stroke a resistance path for the liquid flowing through the piston assembly is formed by the space under the edge of the collar 46 and the passages 38 through the valve member 44.

At the beginning of the outward stroke the piston 20 comes into contact with the valve member 44 and during the movement that leads to this the liquid between the piston 20 and the valve 44 is forced through the port 33 out of the space that existed between the two on the inward stroke, thus materially reducing the halt or check in the pumping. The position of the parts on the outward stroke is shown in Figure 11.

To illustrate the effects produced, some figures will now be given. These were all obtained with a pump holding a quart of liquid and with a hollow piston rod of standard size for such a pump. With the arrangement shown in Figures 1 to 9 the volume of liquid expelled on the downward in-stroke was 18 /2 ccs. and that on the upward out-stroke l1 ccs., giving a figure of 29 /2 ccs. for the double stroke and making the second volume about 60% of the first. When the projection 42 was omitted the first volume fell to 17 cos. and the second remained unchanged, the

percentage rising to about 65%. With the arrangement shown in Figures 10 and ll the first volume fell to 13 cos. and the second was still 11 ccs., making the percentage and reducing the total volume on the double stroke to 24 ccs. These figures, although not so good as those obtainable with two valve members, are good enough for the pump to be an efiicient fire extinguisher. When, however, the valve member 44 was placed on the other side of the piston 20, that is to say, the side remote from the handle, the volume expelled on the downward in-stroke was 17 cos. but that on the upward out-stroke only 6 /2 ccs., which is not enough for the pump to be a useful fire-extinguisher. Finally, when both valves were omitted, the figures were 13 cos. and 6 /2 ccs. respectively.

I claim:

1. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough, and a movable valve member having a liquid passage therethrough carried by and cooperating with said piston and resisting but permitting some fiow of liquid through said piston and valve member passages differently during the two directions of movement of said piston assembly.

2. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure on the liquid therein durin both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough, and a movable valve member having a liquid passage therethrough out of alinement with the piston passage and carried by and cooperating with said piston and. resisting but permitting some flow of liquid through said piston and valve member passages differently during the two directions of movement of said piston assembly.

3. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a, liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough, and two movable valve members each having a liquid passage therethrough carried by and cooperating respectively with opposite sides of said piston, thereby resisting but permitting some fiow of liquid through said piston and valve member passages differently during the two directions of movement of said piston assembly.

4. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough, two movable valve members each having a liquid passage therethrough and cooperating respectively with opposite sides of said piston, and! rods secured to said valve members and sliding through said piston so that said valve members move in unison relative to said piston, whereby said piston assembly resists but permits some movement of liquid through said piston and valve member passages difierently during the two directions-of movement of said piston assembly.

5.,In a hand-operated double-acting pump, a Dump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough, two movable valve members each havin a liquid passage therethrough out of alinement with said piston passage and carried by and cooperating respectively with opposite sides of said piston, thereby resisting but permitting some flow of liquid through said piston and valve member passages differently during the two directions of movement of said piston assembly.

6. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exertin pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a plurality of liquid passages therethrough and two movable valve members each having a plurality of liquid passages therethrough out of alinement with said piston passages and carried by and cooperating respectively with opposite sides of said piston, thereby resisting but permitting some flow of liquid through said piston and valve member passages diiferently during the two directions of movement of said piston assembly.

7. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough and an annular groove in a face of the piston in alinement with said passage, and a movable valve member carried by and cooperatin with said piston and having a liquid passage in alinement with said annular groove in the piston, thereby resisting but permitting some flow of liquid through said piston passage and said groove and said valve member passage differently during the two directions of movement of said piston assembly.

8. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exertingpressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a liquid passage therethrough and an annular groove in a face of the piston in alinement with said passage, and a movable valve member carried by and cooperating with said piston and having'a liquid passage therethrough out of alinement with said piston passage but in alinement with said annular groove in the piston, thereby resisting but permitting some flow of liquid through said piston passage and said groove and said valve member passage differently during the two directions of movement of said piston assembly.

9. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure onthe liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a plurality of liquid passages therethrough and an annular groove in a face of the piston in alinement with said passages, and a movable valve member carried by and cooperating with said piston and having a plurality of liquid passages out of alinement with said piston passages but inalinement with said annular groove in the piston, thereby resisting but permitting some flow of liquid through said piston passage and said groove and said valve member passage dilferently during the two directions of movement of said piston as sembly.

10. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, and a piston assembly reciprocatable in said cylinder and exerting pressure onthe liquid therein during both directions of movement and comprising a piston carried by and movable on said piston rod in cooperation with the passage therein and having a plurality of liquid passages therethrough and anannular groove in a face'of the piston in alinement with said passages, a movable valve member carried by and cooperating with the grooved face of said piston and having a plurality of liquid passages out of alinement With'said piston passages but in alinement with said annular groove in the piston, another movable valve member carried by and cooperating with the other side of said piston a projection arranged to close passages and prevent the faces of said piston'and valve member from engaging, thereby resisting pistonpassages and said groove and said'v'alve member passages differently during the two directions of movement of said piston assembly.

11. In a hand-operated double-acting pump, a pump cylinder, a hollow piston rod having a liquid passage therein, a piston assembly carried by said piston rod and reciprocatable in said cylinder and. exerting pressure on the liquid therein during both directions of movement and comprising a piston carried by and movable on the latter is at its extreme position away from said piston, whereby said piston assembly resists but permits some movement ofrliquid through said piston and valve member passage differently during the two directions of movement of said piston assembly.

RICHARD ZIESQHANG; 

